Switching device for telephone systems.



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SWITCHING DEVICE FOR TELEPHONE SYSTEMS.

APPLICATION FILED JUNE 8, I915- Patented Jan. 9, 1917.

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newand useful Improvements in Switching heads 49 and 50 are of nonmagnetic mate- UNITED STATES PATENT OFFICE.

R 1,211,612. Specification of Letters Patent. Patented Jan, 9, 1917, Application filed June 8, 1915. Serial No. 32,847.

ZbaZZ whom it may concerml similar substance which will serve to in- 55 Be it known that I, DANIEL D. hircnnn, a sulate adjacent ones from each other, there citizen of the United States, residing at by decreasing the eddy current losses and New York, in the county of New York and improving the efiiciency as an impedance coil State of New York, have invented certain to high frequency currents. The spool- Devlces for Telephone Systems, of which r al. the following is a full, clear, concise, and The relays heretofore used in the bridged exact description. impedance type of telephone connectin cir- This invention relates to telephone cuit, while operating efficiently on irect switching devices, and more particularly to current for signaling purposes, were of low an electromagnetic device which will operimpedance tothe high frequency or-talking' ate efficiently upon direct current but will currents. Consequently, the distance over offer a high impedance to alternating-curwhich satisfactory telephone conversation rents of talking frequencies. couldbe carried on was necessarily quite The object of this invention is to provide limited. In any of those relays the core and a relay of this type which will be simple in armature is such that, when the relay is opconstruction, can be manufactured at a moderated, the flux density or the degree of magerate cost, and which willhave a high opernetizatlon is approximately the same in ating efficiency. both the core and the armature, and ap In accordance with this invention a reproaches closely to the point of saturation. lay is constructed in which the core is com- In his condition, which necessarily is the posed of a plurality of superposed sections one obtaining while conversation is being of different lengths whereby a plurality of held, the permeability of the core, and conmagnetic circuits, including air-gaps of. difsequently the impedance of the 0011 to highferent lengths, are provided. Preferably frequency or talking currents, is very lowthe core is composed of one long section ex- Since this low impedance -is bridged across tending through the spool-heads, and the talklng strands of the connecting cirshorter sections located between the spool- 1. i i cl ar tha the talking efficiency of heads. The shorter sections may be com the system as a whole is materially reduced. posed of laminae which are e ured to the In the relay herein described this condition 35 long section by riveting or similar means. has been overcome by the use of laminae, In the drawings illustrating this inven- Which provide a plurality of magnetic cirtion, Figure 1 is a perspective view of an ascuits, including air-gaps of difi'erent lengths, sembled relay in which this invention is emas before described. As is well known, the bodie and Fig. 2 is a perspective view of action of an air-gap in a magnetic circuit the spool-heads and core of a relay embodyis to reduce the flux therein in two ways,- ing the invention. first, by increasing the total reluctance of The relay, so far as it is shown in Fig. 1 of the magnetic circuit, and second, by opposthe drawing, is precisely the same mechaniing the production of the flux by the decally as that shown in thepatent to Edward magnetizing effect of the ends. Thus, by B. Craft, 1,121,897, issued December 22, this action in the relay herein disclosed a 1914, and reference is made to this patent for portion of the core is unsaturated and of a description of these details. high permeability to big -frequency or talkhe invention is illustrated in detail in ing currents. A relay is thereby obtained Fig. 2. As shown in this figure, the shank which operates efliciently on. direct current portion 2 of the core has secured to it upon to perform its function as a signaling deopposite sides thereof a plurality of laminae vice, and atthe same time, due to the unsat- 5, 5 which are shown as abutting against the urated portion of the core, offers a high iminner faces of the spool-heads 49 and 50. pedance to alternating currents of talking These laminae 5, 5 are preferably the same frequencies. width as the shank portion 2 of the core and The only change necessary to adapt this are secured thereto by rivets '7, 7. These feature to the relay described in the Craft laminae may be coated with lacquer or some patent hereinbefore described is the addition of the laminated sections to the core. of the Craft relay and possibly an increase in the diameter of the Winding.

What is claimed is: a 1. An electromagnet posed of a plurality of of difierent lengths.

2. An electromagnet having a core composed of a long section and a plurality of shorter sections superposed thereon.

3. An electromagnet having a core comhaving a core comsuperposed sections posed of a long solid section having a plurality of shorter sections of lamina secured thereto.

4. In an electromagnet,

a pair of spool- 

